Method of making a composite cylinder



@et E956' H. P. SPARKES ET AL METHOD OF MAKING A COMPOSITE QYLINDR 4Sheets-Sheet 1 Filed April l, 1953 @et 9, i955 H. P. SPARKES ETAL765,526

METHOD oF MAKING A coMPosTE CYLINDER Filed April l, 3.953 4 Sheets-Sheet2 I! @o @o if 9,1956 H. P. sPARKEs ET AL 765,52

METHOD 0F MAKING A COMPOSITE CYLINDER Filed April l, 1953 4 Sheets-Sheet3 INVENTORS Har@ l? Sprkes H. P. SPARKES ET AL METHOD OF MAKING ACOMPOSITE CYLINDER 4 Sheets-Sheet 4 Filed April l, 1953 nite States2,765,526 METHOD oF MAKING A CoMPosITE CYLINDER Application April 1,1953, serial No. 346,198 1s claims. (ci. 29460) This invention relatesto a novel method of making a composite cylinder, particularly one offerrous and copper layers bonded uniformly to each other over theirinterface zone. More especially, this invention pertains to a new methodincluding arc overlay welding for making and controlling the joining ofsuch cylindrical layers. The invention has marked utility in providing,for example, composite steel and copper brake drums, with fins, ifdesired, shaped in the copper layer.

' In the field of brake drums, a conventional metal used in cast iron.Many endeavors have been made to employ steel for that purpose withoutmarked general success. In heavy-duty service particularly, on truckfleets, for example, both cast iron and, to an even greater extent,steel drums when used or tried suifered from a number of shortcomings.Thus, a relatively short life was the rule rather than the exception andmany ferrous drums would distort or `develop heat checking on thebraking face with consequent impairment of the braking function and ofthe brake linings. Sometimes, in braking heavy-duty equipment with drumsconstructed by prior methods excessive heat was generated causing brakefading in some cases as a consequence, for example, of the tendency ofthe drums to enlarge or of the lining to begin to break down ordeteriorate. On the other hand, any manufacturer of composite brakedrums utilizing a ferrous braking tube and a metal layer of higherthermal conductivity joined thereto encountered a host of problems which-maintained the use of all-ferrous brake drums long after compositebrake drums as such were known.

Under the'present invention, a new method is made available whichenables composite brake drums, for example, to be'provided which vastlyoutperform prior brake 'drum's'made'by earlier methods. Further, suchcomposite brake drums made by the new method of this invention fare ableto successfully compete in the market place even 'with all-ferrous brakedrums. By the new method hereof, a-steel brake tube may besatisfactorily employed withous causing, in use, the development of heatchecking on the braking face and without distortion of the drum itselfproduced vby the new method. In addition, the new method enables a bondto be provided between steel and copper layers at their interface zonewhich is controllable so that the joinder is uniform over the area ofthe interface zone and uniform radially, thereby neither weakening thesteel brake tube "nor producing excessive iron content in the copperlayer. Preferably, ns are provided on the outer surface of the copperlayer by rolling with significant saving of that metal. In use,`there isnot only a vast increase in the life 'of a composite brake drum made bythe new method hereof but there is also a Vast increase in the life ofthe brake linings associated therewith. -Another feature of the newmethod is its flexibility in respect of enabling a plurality of sizes ofcomposite brake drums to be readily constructed, with assurance that inservice the old frequency of occurrence of heat checking, drumdistortion and brake fading will be drastically reduced or virtuallyeliminated. In addition, because of the advantages of the new methoddescribed herein operation of Patented Oct. 9, 1956 composite brakedrums so made will occur at relatively lower temperatures with less wearon linings and drum and with vastly increased life, safety and economicsavings.

Other objects and advantages will be apparent from the followingdescription and from the drawings which are illustrative only in whichFigure l is a side View, partly in section taken along line I-I ofFigure 2, of a brake drum tube which may be used in a practice of thisinvention;

Figure 2 is an end view of the brake drum tube shown in Figure 1;

Figure 3 is a Z-shape rolled member which may be used in making a brakedrum tube such as the one shown in Figure 2;

Figurel 4 is an end View of the Z-shape shown in Figure 3;

Figure 5 is a view, partly in section along line V-V of Figure 6, of acopper sleeve fabricated and lutilized in a practice of this invention;

Figure 6 is an end view of the copper sleeve shown in Figure 5;

Figure 7 is a perspective view of the copper sleeve of Figures 5 and 6,partly broken away, assembled with and fastened to a steel brake drumtube such as that Shown in Figures 1 and 2;

Figure 8 is a view of a subassembly such as that shown in Figure 7mounted on a rotatable positioner in juxtaposition to a submerged arcoverlay welding head, certain equipment parts being omitted forclarication;

Figure 9 is an end view of the set-up shown in Figure 8 with provisionfor heating and cooling the aforesaid subassembly as desired and forremoving fused flux scale produced in a welding step;

Figure 9A is a detailed view of a distributor for heating or cooling theafo-resaid subassembly as desired;

Figure 10 is a fragment of the aforesaid subassembly after the coppersleeve has been built up into a copper layer of desired thickness andthe steel and the copper layers have been uniformly bonded throughouttheir interface zone;

Figure 11 is a view of a brake drum made by a practice of thisinvention, after copper has been added, which may be engaged by a sizingdevice in the course of a heat treatment, if desired;

Figure 12 is a view of the brake drum shown in Figure 11 mounted on avertical lathe for preliminary exterior surfacing;

Figure 13 is a view of the brake vdrum shown in Figure 12 in mountedposition for engagement with nning rolls to produce fins in the outerportion of the copper layer of the composite brake drum;

Figure 14 is a fragment of a substantially nished coinposite. brake drummade Vby a practice of this invention after fins have been rolledtherein as shown in Figure 13;

Figures 15 and 16 illustrate finishing steps on the brake drum bore,other edges and surfaces thereof;

Figure 17 illustrates a jig drilling operation o n the bolt flange ofthe composite brake drum shown in Figures 15 and 16;

. Figure 18 is a side View, in section, taken along line XVIII-XVIII ofFigure 19, of the finally finished and drilled brake drum sho-wn inFigure 17 with a wheel adapter fastened thereto;

Figure 19 is an end View of the structure shown in Figure 18;

Figures 20 and421 illustrate another method of providing a heavy-dutyservice brake drum tube which may be utilized in a practice of thisinvention;

Figure 22 is an illustration of a practice of this invention utilized inthe making of an externally contracting type of brake drum; and

Figure 23 is a sideview, in section, of a. composite brake drum afterconstruction and finning of the kind shown under construction in Figure22.

Referring 4t'o Figures 1 to 4 ofthe drawings, a'practice of thisinvention may utilize a ferrous rolled Z- shape which is suitable forheavy-'duty service. Shape 10 is bent into cylindrical shape 11 withheavier ange 12 outwardly to form an integral reinforcing Iring 13 wherethe composite 'br-alte drum tube 11 is to be utilized with internalexpanding brakes on trucks, buses and other heavy-duty automotivevehicles. The ends of shape 10`i11 .the 'course of being formed intotube I14 are flash butt Welded at 14 which completely unites `therrietai 'andiunder present-day joint flash bu'tt welding practice can bedone so that very little metal remains fo bernachined off. AIn 'suchformation of tube 11, further, Iflange .1'5 f shape 10 becomes 'inwardlyextending bolt liange 16. Other modes may be utilized withoutdeparting-from this invention, in eonstrriotinga brak'e drum tube offerrous metal, such as steel. Thus, as shown in Figures '20 and 2'1,`a-rolled flatstr'i'p 17. may be united with a ring 18 by weld metal 19.Similarly, fa bolt flange ring 20 may be uni-ted with strip 17 after ithas been cylindrically. formed and the ends thereof Welded, to the`other end of tube 17 by weld metal 21. Or, if desired, .a ferrous brakedrum. tube may be formed from a rolled L- shapethebase of the L beingeither a reinforcing ring .component or a bolt flange ring component, sothat-only the component not incorporated in the L-shape needs to bew'elded after the L-shape is formed into a tube, in accordanc'e with theappropniate showing at either end of rthe tube shown in Figures 20 and21. Again, a suitable brake drum 'tube may be made, if desired,beginning with a pierced ycylinder in which there is no axial weld jointand rings for the reinforcing ring or the bolt ange ring or both maybefabricated as rings or may be linear strips of suitable cross sectionwhich are bent into round form and suitably welded. In that connection,although the embodiment being described employs a reinforcing ring, suchrings are particularly useful lin heavy-duty service Vand WouldAnot berequired with lighter automotive vehiclesf In the latter case the brakedrum tube would consistof a cylindrical bcdy and a single bolt flangelike flange 16.

,A ,Eollowi'ngtthe construction of a suitable brake drum tube, like tube11 in the rough, tube 11 may be mounted Quia .vertical turret lathe for,rough turning of the surfaces thereof including the bore 22 or faceagainst which @brake liningwill actin the embodiment Yshown in theexterior s urfacef23 of. thebody 24 of tube 11. In such machining,surfaces 22 and 23 are maintained concentric andnatleasturface.23 is atthat time given an intermediate riish,by.machining it While in suchconcentric relation torbore 22., .In addition, discoidal surfacel25 ofange 13 is also provided with an intermediate finish bynmachinin'g.;-Q'ther. modes of accomplishing the respect- Ative-roughand-intermediatefinishing operations may be employed as ,Will be..unders`tood by thosein the art to whomthisV invention is disclosed.,

Generally speakingsteel brake drums have not proven .satisfactoryHowever, a .composite brake drum` constructed Ain accordance withapractice in this invention enables a brake drum tube, like tube 11, tobe made of steel. *,VI'hussteel's ofthe ,following ferrous compositionswith vvtheir alloyingconstituents appear to be 'ainor'ig those unizhafaatifacwrv After tube 11 is rough turned and intermedi'ately 1lin- 4ished as hereinbefore described, a sleeve 26.of.copper..is placed oversurface 23 and generally will extend from face 25 to face 27.Preferably, the copper in sleeve 26 may be phosphorous-deoxidized and befrom a non-electrolytic refining process. Sleeve 26 may be made from aflat copper. strip or plate formed intothecylindrical,shape shown inFigures' 5 and `6 and welded along the abutting ends forming joint 28..A suitable-weld may be produced using an.inert 'gasshielded arc withstandard welding equipment of that character, utilizing copper weld Vrodof compatible nature tothe naturerof the cojgple'r in sleeve 26.Generally, the inside diameter of sleeve 26 will 'relatively closely t'against the outside diameter of .body 24 so that surface 23 is injuxtaposition to the inside 33 of cylinder 26. Such a subassembly oftube 11 and sleeve 26 may have the sleeve Welded to body 24 by'weldingbead lines 29 and 30 around the edges 31 and 32 respectively. Equipmenthereinbelow described may be utilized to form the welds 29 and 30 whichhold surfaces 23 andl 33 together along ythose weld lines. The .weld-inglinet29 is preferably not joined to flange surface 25-of reinforcingring 13. c

In apractice of this invention being described, a subassembly lof a tube11 with a sleeve 26 thereon may be mounted on a positioner 34.Positioner 34 may clom- -prise` a tilting gear 35 supportingan arbor 36rotatable relative to the axis of arbor 36 by aA ring gear 37 fastenedto a positioner table 33 -at the outer end of arbor 36.V A shield 39 maycover a sprocket vpinion 40, a sprocket chain 41 nand a bevel gear 42 tomesh with ring lgear.37. Pinion 4) may be driven at any selected rate of.speed by. suitable means (notshown.) such as a variable .speed electricmotor to produce a given rotational speed in subassembly 43 comprisingtube 11, sleeve 26 and additional copper deposited around the exteriorof brake drum subassembly 43 as it is revolved in the direction of.thearrow 45. Fastening member 43 to table 38 may normallyY be done whentable 38 is in a horizontal position,.dogs' and bolts of conventionalnature being used to clamp against internal flange surface 46 of thebolt ange. After such clamping,.a handwheel 58 may be usedtto turntilting gear 35 until axis 5S of the brake drum subassembly 43 ishorizontal and thespeedof rotation .of .drum43may be controlled by a.speed control lever 59 connected to the aforesaid motor through suitableelectrical or other speed control equipment. Positionen 34 maybe mountedon a. base 47 and provided with a box receptacle-1.8` having thetop-thereof covercd by ascreen ,49 fastened .tothe bottom of a removableupwardly and outwardly aring edge 50 tting around the top edge ofbox48.- 4A welding `assembly ,S1 is supported on a structural traversingrail 52 along which it may move in engagement withl a. rack.jastenedftorail 52. In its movement, welding head 54 .of assembly 51moves .parallel to the axisSShof. subassembly 43 which axisiseoincidentwith the .axis.,.ofarbor 36 about which subassemblyV 43 is rotated by,positioner 34 in thecourse .of o eration in a practice. ,of this.invention being described. t Head 54 is so constructed.and arranged that.a consumable copper wire electrode 56 is Vunreelccl and fed betweenstraightening andfeeding rolls 57, the `end 69 of rod .or .vire.56emerging vthrough a central opening. in,head.54.. the arc by mean'sofwhichrod 56 is melted and overwelded to theexterior of subassembly 43.existing betwecnsubassembly 43 and the tip 6,9. In the course of.suclrwelding, the arc created is submerged by a powdered or granularflux contained in a hopper 61 which flows downwardly :around rod 56 andout of 4head 54 around tip 66 toa suicient extent to Wholly submerge thearc consuming tip 61) anddepositing molten copper weld onl the exteriorof subassembly 43'. "l'he vertical center line through 'tip' 6l) i`spositioned on the leading side of a vertical plane through axisSSasshown on Ii'gure 9. Head 554 rnay be tilted universally by virtue of theslot and bolt connections 62 and the turnplate connection 63 to thebalance of the welding head structure, suitable handwheels or othermanipulators being provided to hold head 54 in any position desired.Preferably, for -a practice of this invention being described, head 54is vertical as is `tip 60 of the consumable copper rod 56. -Rod 56 is ofthe Isame nature as the copper in sleeve 26. A laterally extending framemember 64 -of assembly 51 carries wires to ythe motor generator set (notshown) sup plying the power for the arc welding operation performed asshown in Figures 8 and 9. Generally, a steady and more constant lengthof yarc appears to be obtainable when using direct current weldingequipment. 'In addition, an electronic tube control for the feedingaction of rolls 57 and associated mechanism may be provided which feeds-rod S6 in la suitable manner to maintain a relatively unvarying arccharacter in the course of an operation under this invention.

A switch panel `65 may be used with suitable buttons -thereon forcontrolling Ithe `traverse of head 54 along rack 53 in proper speedrelation lto the speed of revolution of subassembly 43 so that in `thebuilding up of a copper layer 66 on a steel layer 24, such copper layerincorporating sleeve 26, the welded band yof added copper will be in theform of a helix extending from flange 13 to, in the embodiment shown,face 27 adjoining table 38. The spiral turns of added copper produced bythe submerged arc welding step are su'iciently close axially land thepitch of the helix -suiciently small so that no substantial valleys orfurrows are present where one turn or band of copper is thus added nextto another. It may be that the temperature of the welding operation andother conditions are such that suiiicient fusing of ythe lateral edgesof the molten deposit from tip -60 are produced to cause a leveling outof the top surface of the added copper and layer 66 parallel to axis 55as the welding operation proceeds. Valve 67 at the base of hopper 61 maybe used to regulate -the flow of lflux so that an appropriate quantitywithout any excess yor deficiency iiows around tip 6i) to submerge thearc and perform the desired fluxing operation. After subas-sembly 43 isclamped lin place and arbor 36 turned into a horizontal position, ahandwheel 68 may be used to position assembly 51 in the position shownin Figures 8 and 9 for Ithe start of a coppenaddition submerged arcwelding step, after assembly 51 has been utilized to provide fillet orfastening beads 29 and 3ft.

As the addition of molten copper proceeds on Vthe exterior of thesubassembly of drum 43, Athe ilux concealing the are lbetween tip 60 anddrum 43 may become fused ,in part and adhere to the outside of the addedcopper 'annulus. A cross arm "69 may be connected to movable assembly 51so that as head 54 is traversed cross arm 69 is moved correspondingly. Awire Ibrush 70 may be mounted `on a bracket 71 on cross arm 69 androtated by a compressed air motor 72 receiving compressed air from -aflexible hose 73, the -direction of rotation `of brush 70 being the sameas the direction of rota-tion of drum 43 with lthe result that any fusedflux willbe brushed off the exterior of drum 43 into the contines oflthe edges 50 on top of box 48. vSince fused `iiux generally will belarger than the unfused granular flux which helped submerge the 4arc tip6i), unfused reuseable -ux will pass Ithrough screen 49 into the bottomIof box 48 while the fused unreuseable ilux iiakes will be held o-nscreen 49 in the upper portion bounded by the edges 50, the mesh ofscreen 49 being properly selected for that purpose. From time to time,Ibox 48 can 'be removed and the fused flux particles -on screen 49thrown o-ut while the unfused iux in the bottom of box 48 can bereturned to hopper 61. An electric or pneumatic axial hammer 74 may alsobe attached to cross arm 69 to rapidly tap drum 43 and insure `thesubstantially complete removal of fused ilux from the annulus or overlaybeing added on the exterior of drum 43. Because of the traverse of crossarm 69 with head 54, hammer 74 and brush 70 are always operative on thelast pitch -or turn of the overlay annulus then in the course of beingmade.

As shown in Figures 9 and 9A, a `bifurcated distributor '75 constitutesa connecting chamber for two parallel manifolds 76 provided withopenings 77 in a row -along the surface thereof, which lopenings 77communicate with the interior of the manifold 76. A supply pipe 7S maybe used to conduct a combustible fuel gas and air mixture intodistributor and manifold 76 whenever it may be desired lto lheat drum43. Conversely, air or other `cooling fluid may instead be forcedthrough pipe 78 so as to ow out through openings 77 against `bore 22Whenever it may 'be desired to cool `drum 43. Suitable valves (notshown) are connected between pipe 78 and the respective heating andcooling gaseous sources.

In a practice of this invention, following the above described machiningof tube 11 and the fitting thereover of sleeve 26 after removal of anyprojections inwardly of surface 33 along the weld line 28 by means, forexample, of 'a -bufling wheel, such tube and sleeve may be mounted lonpositioner table 38 as described in connection with Figures 8 tand 9.Fuel gas and combustion air or fuel gas alone may be passed through pipe78 and ignited where the gas issues from the openings 77, which openingsas shown -n Figure 9 are Iturned toward the inner surface or boresurface 22 `of drum 43. During the heating of drum 43 to a temperaturepreferably from about 350 F. to about 400 F., drum 43 is rotated bypositioner 34 as described. The fuel gas is shut o from pipe 78 when latemperature recording instrument like a contact pyrometer indicates thatthe preheating of drum 43 before there has been any overlay has beenaccomplished. Head 54 may be brought into position by movement alongrack 53 adjoining table 38 as shown in the solid line outline in Figure8 and tilted `slightly so that tip 60 tends 4to poin't away from table3S. Thereupon, the arc may be started and welding line 29 performedstraight around edge 31, the traverse mechanism of assembly 51 beingthrown out of gear during that welding step. Then, head 54 may be movedto the position shown in Figure 8 in dotted outline and welding bead 30made while t-he traversing mechanism of assembly 51 is held out ofengagement to permit the bead to follow edge 32 of 4sleeve 26. Whensleeve 26 is thus welded to body 24 along both edges thereof before anoverlaying welding step commences, it appears that there Iis nomateri-al axial shrinkage of sleeve 26 and, in addition, there appearsto -be no interference with the overlay welding operation either in theuniform, level lbonding obtained therebygor, by way of occlusions in thecopper layer 66. I

To `start an arc, after the welding current equipment is turned on,either head 54 may be lowered until tip 60 touches drum 43 and then tip6i) may be retracted, or, a lball of steel wool may be placed withinsulated tongs between ltip 69 and drum 43 under a flux cover fromhopper 61. After the beads 29 yand 30 a-re made, lthe overlay heliximmediately on top of sleeve 26 maybe started adjoining bead 29 with theautomatic traverse mechanism including rack 53 of tassemblyvl inengagement and timed in correlation with the revolutions per minute ofdrum 43, the rate 'at which consumable electrode 56 is fed and thedesired voltage and current conditions suflicient to yield |a uniform,level bond in lthe interface area where bonding takes place. Suchinterface area may be thought of fas a thin hollow cylinder 79 wheresurfaces 23 and 33 met ybefore the submerged arc overlay welding stepoccurred by means of equipment illustrated in Figures 8 and 9. After anoverlay helix or annulus is made extending between iiange 13 to a pointadjacent face 27, or rather between bead 29 and bead 30, the respectivesurfaces 23 and 33 and the met-al immediately adjacent thereto inmicroscopic radial depth, bond together. Significantly, such ybondingoccurs `p'osite brake drum 4include `separable stave elements eventhough the yarczfits'elf extends between electrode' tip 60 and the outerportion of sleeve 26., Thi's', it appear that the arc not only fuses theAend of `rod :s it being fed downwardly but also makes the portion ofsleeve l26 immediately therebeneath and the portion of surface 23immediately therebeneath molten to a controlled extent which producesbonding of copper to steel and bonding of a copper overlay band 'or beadto a copper sleeve without excessive radial penetration linto body 24.which wenn weaken n and the Strength of the admi posite brake drum inwhich tube 11 is used. YFurther, such a controlled operation alsomaintains any take-up of iron in the copper at a figure which does 'notimpair the functioning of `a compositebrake drum made under thisinvention. Above about .4% of iron in copper within cylindricalinterface area 79 the thermal conductivity of the copper layer 66 levelsoff, relatively speaking. Hence, iron contamination evenup to 1ak ligureof about 2% iron in copper within a'rniilar cylinder 79 and adjacentthereto in layer 6,6 yields efficient heat equal-i'atio'n around theentire circumference of tb'e y11 ,when in servieeas a part of acomposite brake drum with excellent heat dissipation qualities. .u Itappears that what may happen is that as the 'assembly rotates, oneobtains 'a constantly moving 'mold rounding the axis of tip 6) whichkallows the metal passing `out beyond the mold lconfinement on the,after side of head 54 to solidify effecting the aforementionedbondingwhile the new unbonded portions of sleeve 26 and tube 11 entering`the arc zone begin t'o melt and bond while retaining their substantiallayer identity throughout the relatively short time they are 'in theriolten bondipromoting state. In -any event', `and without beingllinited to the statement of theory as 4to the operation which may takeplace in the manner ofa small confined and Iconstantly moving moldsubstantially at the verywtc'tpfof a brake drum cylinder being overlaidwith additional lcopper while its axis is generally horizontal, a'composite brake drum produced in yaccordance with this invention doeshave an interface zone which being quite precisely parallel to the axisof the brake 'drum and which, further, is bonded `over each unit :ofarea of the interface zone. As a consequence, composite brake drums soproduced ontlast and outperform vfall prior brake drums and `are enabledto use steel tubes las a part of `their construction without producingheat checking 'or brake fading or drum distortion out of round. Inaddition, the braking characteristics remain superior and brake liningswith composite brake drurns produced hereunder `ontlast and outperformthe same brake drums.

In a practice of this 'inventionvbeing described, 'after hea'd`54 makesone axial pass Ythe'radial Athiclnessoflayer -v66 maycomprise'forexample, theftliclness 'of sleeve 26 plus the thickness of the overlay'annulus 8G, embodiment described, 4a second overlay annulus 81 'stillVto b'efadded. For'illustrative purposes only, afalnt line risv shownon'layer 66 Ain Figure Al0 as a possible schematic showing of theexterior vsurface of sleeve 26 'and of the exterior surface of the firstcopper addition annulus 80, although it will be recognized that 'in themethod 'of this invention, there are no sch lsurfaces or demarcationsbecause of the welding 'and Vfusion which takes place "in buildingcopper layer 66 up to the thickness desired by producing one vor moreoverlay afrinul-i of copper on Vtop of and. Vfused -to sleeve 26 and torubell. Preferably, following the vproduction of the ''rst or innermostanvnulus layer 86 in the described practice, it'in'ay Vbe desired tostress relieve or to heat treat the 'unfinished com- '43, particularlyin order to tak'effull advantage of the properties of 'alloy steelfwhensuch is used 'in the vmaking of a tube Il. `One mode 'of such stress'relief or `heat treating may also 4employ 'a f sizing fixture S2, ofconventional nature.y Such fa 'tixturelmay is level in the sense ofbrake linings used with prior t with, in the s3 'experimentada-:fthe

dit-35,3%

ce of pyrnidl 'male expander member 84 en gagging correspondinglytapered inner sides on said staves 83. St'a 83 may be held in generalassembly arrangenient in expanderinember 84 by splitrings 85 incomplenenta'ry grooves around the exterior of the staves so that whenthe staves and expanded member .are positioned within bore 22, Isplitrings v85 will not 'engage bore 22. A bolt land nut assembly S6 may havethe bolt thereof extend through the center of the expander memb'e'r 84lso Athat when bolt assembly 86 is tightened base 87 anda plate 88 tendto move staves 83 in an opposite axial direction to member 84 untilsizing device 82 rmly grips drum 4'3 to hold it, if desired, in correctsize and without permitting any rdistortion of drum 43a to take place inthe 'corse of any heat treatment that may be ac'c'ordedvto the d'rurnafter one or the other of Iannuli S) and 81, 'in the described practice,'is applied. Indeed, any heat treatment and use of a sizing device, if'desired, like device 82, may be reserved until drum 43a is completelyfinished, except that where ns are provided on the completed drum, caremust be ltaken not to mash or lotherwise damage such tins or the balanceof the copper layer. 'Regardless of whether -a sizing device 82 isemployed, it Vis preferred after each overlay Aannulus, that drum 43a be'slowly cooled, as by being buried in .un- Slaked lime until thetemperature of the drum 43a reaches a temperature when 'so cooled notabove about 200 to 300 F. A similar Vprocedure is preferably followedafter a second overlay annulus 81 is added. Such slow cooling usuallyachieves stress relief `and for particular services, no h'eat treatmentmay be desired. ln lheat treating, as distinguishedfrom a `slow coolingstep mentioned herein, Ia drum 43a 'might be heated to an approximatehardening temperature in the neighborhood from labout 1550 F. to about1600 F. and held at that temperature for about onehour Aafter which aysizing fixture likevxture S2 may be applied to insure desireddimensioning of drum `4521, following which the xture and drum can bequenched in oil or other suitable quench medium, after which the xturecan be contracted and the drum removed. An appropriate heat treatmentfor a particular composition of 'steel employed in a tube like tube 11when bonded vto copper in the manner disclosed in this invention, willbe `a subjectand understood by those in the heat treating lart tokachieve desired qualities of hardness, strength and strain-freecondition.

Following the completion of the overlay welding step or steps heretoforedescribed, drum 43a may be mounted Von a vertical lathe table 89 yandrotated to enable tool '90 to turn -.olf jany vrough or high spots onexterior surface 191. Thereby, `a relatively smooth surface 92 is'provided against which a Ygang roller 93 may be pressed to'produce nsin the outer portion of copper layer 66. For a nning step, drum 43a maybe Vmounted 'hori- 'zontally on vantexpanding mandrel arbor 94 androtated as shown, for example, by the arrow in Figure 13. During suchrotation, gang roller 93 may be pressed ra- Idially a'ndprogressivelyinto outer portion of copper layer 66 Athrough its journal 9S andbracket 96, a thrust rod 97 having mechanism (not shown) forcoordinating ,the radially inward movement of tool 93 with therotational speed of drum Aagon mandrel 94. Tool 93 comprises a pluralityof hardened steel tin rolling disks 98 in sideby-side relation onjournal 95. Significantly, such a lin rolling step isecononiical ofmetal. lt appears that in such fin rolling, the 'outer portion of layer66 adjacent surface 92Vis displaced substantially in a cold ilow mannerto formtin's 99, the profile of which is chiefly a function of the crosssection of disks 98. The metal saving significance by fin rolling may berealized if the blanket portion ofl layer 66 in Figure 14 is consideredthe portion between body 24 `and theroot line 190 of tins 99, yan'd'such blanket portion is desired to have a thickness of ofan inch, tins99 may have a height, that is a radial dimension from 'root to crest ofabout of 'an inch even though the entire thickness of layer 66 fromSurface 92 to body 24 may be in the `order of @je of an inch. Hence, itfollows that VIif fins 99 are machined in a copper layer, that copperlayer instead of being /16 of an inch thick would have to be 5/8 of 'aninch thick to obtain the same fin height. Further, interface zone 79 ondrum 43h which may be regarded yas its datum level reference after alinning step, as shown in Figure 14, Vis not a true surface but is athin cylindrical bonding zone equidistant from Iaxis 55 of drum 43h andconsists of `a level, uniform joint without separation of steel fromcopper over the entire area of zone 79. Thereby, even if localized heatshould develop on braking f-ace 2212, the conducting of that heat -tocopper blanket 66b where equalization of heat around the entire steelbody 24 is substantially instantly performed .plus the ready and rapiddissipation of heat by the blanket and more particularly by the fins 99,.avoid heat checks, even though body 24 be made of steel, keeps theoperating temperatures of the composite brake drums made under thisinvention lower, prolonging their lives and avoiding the host ofdiiiiculties a-ttendant upon prior braking operations, particularly inheavy-duty service.

Finishing machining may be performed `as shown in Figures 15 and 16 withthe brake drum mounted on a vertical lathe table 101 in `successivepositions shown, the small arrows 102 illustrating the surfaces whichpreferably are more finely nished before the brake drum is shipped. Suchincludes surface 22b, the braking face which preferably -is providedwith a highly smooth finish either by cut-ting tools or, in some cases,by a grinding operation. After finishing, as shown in Figures 15 `and16, drum 43!) may be mounted on a drill press table 103 and a drill jig104 positioned over bolt flange 16 to enable a drill press head 105 anddrill 106 to accurately locate bolt holes through ilange 16 around thelength thereof generally in equidistant relation to one another. Asshown in Figures 18 and 19, la dished steel adapter 107 is selected forthe particular wheel construction on which drum 43b is to be employed.Adapter 107 is provided with a cylindrical flange 108 which closely litsover body 24 adjacent face 27, copper layer 66 preferably endingsomewhat short of face 27 so that the inner surface of flange 108 maybear `against surface 23 between the adjacent end of layer 66 and face27, thereby helping to concentrically center drum 43b relative to thecenter of adapter 107. Bolt holes in discoidal flange 109 of yadapter107 regis-ter with bolt holes drilled in flange 16 of drum 43b, bolts110 or other securing devices being used to attach the two memberstogether. In addition, adapter 107 Iis provided with an inwardlyextending discoidal flange 111 which is provided with holes 112therethrough, which holes will register with the particular wheel 'onwhich the particular adapter and brake drum 43b are to be mounted Iandsecured thereto. Although adapter 107 is shown as dish shaped, otherforms for particular and differing wheels are provided. In this way, arelatively few brake drum sizes may be employed on a much greater numberof different wheels for vehicles.

As an example, and without limitation of this invention thereto,manufacture under a practice of this invention of one of many compositebrake drums possible, may be described, omitting any slow cooling and/orheat treating that may be employed as well as fused flux removal,machining and finishing steps hereinbefore described. Thus, in making acomposite brake drum with a bore of 161/2 inches and an overall width of8%6 inches in the finished state, a steel cylinder with an integral orweldedon reinforcing ring and bolt ange may be machined down an outsidediameter on body 24 of 16.875 inches and to an inside diameter of bore22 of 16.125 inches. A phosphorus-deoxidized copper strip about 1A; inchthick may be rolled into a cylinder and strapped over the outsidediameter of the steel cylinder where the butt joint of the copper stripcylinder may be welded with a silicon*- deoxidized copper rod by aninert vgas shielded welding method using a tungsten electrode and heliumor argon gas for an inert atmosphere. After completion ofthe coppersleeve cylinder, the overlay welding machine head may be moved intoposition and tip 60 kept between about 11A: to 11/2 inches on the sideof a vertical plane through the axis of the drumcounter to the directionin which the drum is rotating. In that position, beads 29 and 30 may beapplied to fix sleeve 26 in its relationy to the steel tube 11. The drumis rotated by the positioner on which it is mounted at a constant speedunder the arc produced between the drum and tip 60, that speed intheexample herein given being between about 271/2.. and 301/2 inches perminute linear speed at the periphery of the drum. The traverse of thewelding headand of. the arc, for the described example, should yieldanlaxial pitch between about .27 and about .33 inch using a copperelectrode of 3/{16 inch diameter and a flux like union melt. The speedof the traverse should also be constant and because of the correlationwith the rotational speed of the drum will provide overlay spiral bandsor beads of weld metal in producing an annulus like annulus in whichthere will be no undue gaps between the bands in the nature of unfilledvalleys nor undue crests, and in addition, the bonding not only tosleeve 26 but the level and uniform bonding of all copper present to thesteel tube will also take place in the interface zone 79. On theelectrical side, a stable steady arc is desirable and in the givenexample may constitute a direct current between about 550 amperes andabout 610 amperes at a voltage between about 28 and 32 volts. The steelused in tube 11 may be in S. A. E. No. 8620 steel, for example. Theelectrical conditions should be maintained just as constant as possibleto maintain sufficient-heat to achieve the extent and character ofbonding producible under this invention. In the course of providing twooverlay annuli of additional copper to complete a layer 66, in thedescribed example, the drum is preheated to about 350 F. by the burningof gas issuing through manifolds 76, before the actual overlay weldingis commenced. During the overlay welding of copper addition steps,compressed air at room temperature is pumped through the manifolds 76and issues through the openings 77 against bore 22 of the drum toprovide a further control in the described practice of this invention.In the described example, the final thickness of layer 66 before firmingis about W16 of an inch, which after the rolling of fins therein willleave a copper blanket of about im of an inch thick and fins of about7&6 of an inch high (measured in a radial direction) bonded to eachother and to the steel of the brake drum tube.

Another practice of this invention may constitute a construction of acomposite brake drum which is to be employed with a vehicle havingexternal contracting brakes. In Figures 22 and 23, illustrative elementsare shown for that purpose, those corresponding generally inconstruction and function to the described practice above havingcorresponding reference numerals with the addition to a prime thereto.Although drum 13b is not provided with any reinforcing ring, because adrum such as that shown in Figure 23 has an added strength factor be'-cause of the hoop strength of the steel tube in the composite drum,nevertheless such a reinforcing ring may be added either as an internalor an external flange if so desired, without departing from a teachingof this invention. Further, in the showing of Figures 22 and 23, aiinning gang roller may be placed at an angle askew to the axis of angle43h' so as to roll fins 99' in a spiral or helical manner, the gangroller being suitably traversed relative to drum 43h' in the course ofsuch iin rolling. In addition, an air blast or vacuum equipment may beemployed to remove loose ilux whether fused or unfused from the interiorof brake drum 4312 in the course of the operation shown in Figure 22 ina manner which will not 1 1 disturb thefsubmergence of the' arc by theux issuing from' head 54 around tip 60'. Similarly, cleaning bers may beplaced inside the interior of subassembly 43 to priornptly remove fusediiux from the outer side of the overlayrannulus, without departing fromthe teaching of this invention.

Various other modifications and alterations may be made in the stepsthat the method and practicings taught by this invention withoutdeparting from the spirit thereof and-the scope 4of the appended claims.

We claim:

1. In a method of making a composite cylinder, the steps comprising, 'incombination, assembling afer'rous membe'r having a surface straight inat least one direction in juxtaposition to a dissimilar :metal memberhaving an adjoining surface which is at least straight in the samedirection, 'said surfaces defining an interface between said ferrous anddissimilar metal members, positioning an arc on the other side of saiddissimilar 'metal member, moving, said arc relative to said members in acontinuous -V path delining an unbroken area overlying said interface,welding addition'metal on said other side of said dissimilar metalAmember with said arc, simultaneuslyA bonding ,said memberstogether atsaid interface, and maintaining suchl relative movement and thecharacteristics of said arc at correlated values so as 'to provideuniform bonding over theentire area traversed by said path with saidferrous member remaining generally constant in thickness.

y A2. lnk a method of making a composite cylinder, the `stepscomprising,in combination, assembling a ferrous member having a surface straight inat least one direcnon in juxtaposition to a copper member having anadjoining surface which is at least straight in the same direction, saidsurfaces` defining an interface between'said V ferrous and. coppermembers, positioning an arc on the other side of said copper'member,moving said arc relative to said members in a continuous path definingan unbrokenarea overlying said interface, bond overlaying additioncopper on said other side of said co-pper member with said arc,simultaneously welding said members together at said interface,maintaining suchrrelative movement and the characteristics of said arcat correlated values to provide bonding over the entire area traversed by said path, said bonding between said members further maintaining saidferrous member generally constant in thickness, and constructing fins insai-d addition copper. A 3. In akmethod of making acomposite cylinder,the steps comprising, in combinatiomprovidinga ferrous tube, forming acupreous sleeve around said tube in juxtaposition to one of the surfacesthereof parallel 'to the Vaxis of said tube, welding 'cupreous additionmetal `t'o the side of said sleeve away from said tube to bond saidtube, sleeve and addition metal together, and helically moving said tubeand sleeve relative to the area of application of said addition metalduring such welding.

4. Ainrapmethod of making a compositecylinder, the Asteps comprising, incombination, providing a 'ferrous-tube, positioning a cupreous sleeveVaroundsaid tube in telescoped juxtapositionto one of the `surfacesthereof-parallel to the axis of said tube, welding cupreous additionmetal to the side of said sleeve away frorn'sad tube to bond said tube,sleeve and addition metal together, helically moving said tube 'andsleeve relative to saidaddition metal as said addition metal is fedduring such welding, land controlling said welding to depositsaidaddition metal and maintain molten .metalsubstantiallyonly alongthe'horizontally upward surface 'area'at the timebeing of said cupreoussleeve.

5. In a method of making a compositecylinder,the :steps comprising, incombination, providingaferroustube, providing a cupreous sleeve,.placing 'said'tube'a'nd 'sleeve in radial juxtaposition,fastening'said'sleeve tosaid tube, mounting and rotating asubassemblyof'said. tube'and sleeve, positioninga 'welding archeadadjacentthe'upper- 'mos'tportio'n of saidsubassemblyfeedingcupreousaddiist tion metal to sa'id portion duringsaid rotation, welding said addition metal to said subassembly on theside of said sleeve away from said tube, simultaneously bonding saidsleeve to said tube, and axially traversing said head .during saidwelding to bond said addition metal to said sleeve and tube in a spiralband over the length of said sleeve.

6. In a method of making a composite cylinder, the steps comprising, incombination, providing a rolled ferrous shape, forming said ferrousshape into a ferrous tube, providing a cupreous sheet, forming saidcupreous sheet into a cylinder, welding the axial joint of said cupreouscylinder, positioning said cylinder around said tube, fastening saidcupreous cylinder to said tube around at least a portion of one edge ofsaid cupreous cylinder, mounting said tube and cupreous cylinder inagenerally horizontal telescoped position, rotating said tube andcupreous cylinder at a predetermined speed, 'positioning an arc overlaywelding head adjacent the top of the subassembly of said tube andcupreous cylinder, said welding head being somewhat to one side of avertical plane through the axis of said subassembly 'counter to thedirection of rotation of said subassembly, feeding a cupreous rod tosupply addition metal through said head during said rotation, andaxially traversing said head at `a predetermined speed correlated to thespeed of said rotation 'and feeding to weld said addition metal to saidsubassembly and said cupreous cylinder to said tube.

7. 'In a method of making a composite cylinder, the steps comprising, incombination, assembling a circular ferrous ltube and a circular cupreoussleeve in concentric relation with cylindrical surfaces thereof parallelt0 the axis thereof and next to one another, simultaneously weldingcupreous addition metal to said sleeve with an are, bonding said sleeveto said tube, rotating said tube and sleeve relative to said arc duringsaid welding at a rate Vsuiiicient to maintain a bonded interface zonebetween said tube arid sleeve equidistant from said axis.`

V8. In a method of making a composite cylinder, the steps comprising, incombination, assembling a ferrous tube and a cupreous sleeve inconcentric relation with adjoining surfaces thereof parallel to the axisthereof and next to one another, welding said sleeve to said tube,simultaneously welding cupreous addition metal to said sleeve in aspiral band having its turns laterally fused and'r'elatively level alongthe outer surface of said addition metal, moving at least said tube andsleeve'during sai-d weldingsteps at a rate sutiicient to maintain abonded interface 'zone between said tube andsleeve equidistant from saidaxis. n

`9. In a method of making a 'composite cylinder, the 'steps comprising,in combination, providing a ferrous tube, providing a 'cupreoussleeve,'fplacin'g said tube'andsleeve inradial juxtaposition, fasteningsaid sleeve to said tube around `at least a portion of one edge of saidsleeve, mounting and rotating'the subassembly of said tube and sleeve,positioning a welding /head'adjacent the uppermost portion ofsaid'subassembly to a side 'of a vertical plane through the axis of saidsubassembly counter to the direction of rotation of said subassembly,feedinga cupreous rod'for addition metal through said head during saidrotation, welding said additionmetal to said subassembly on the side ofsaid ,sleeve away from said tube, simultaneously bonding said sleeve tosaid tube, axially Vtraversing 'said Vwelding head during said weldingto bond'said addition metal to said sleeve and tube in a "spiral band-over the length of said sleeve, and cleaning the surface of saidaddition'metal following said bonding.

l0. VIn amethod of making a composite cylinder, the stepscomprising, incombination, providinga rolled ferrous shape, forming said ferrousshapeintoa ferrous tube, providing -a`cupreous sheet, forming'saidcupreons'sheet into a` cylinder, lwelding, -the axial joint of s aidcupreous cylinder in an inert gas atmosphere, positioning ysaid"cylinder around said tube, fastening said cupreous cylinder to saidtube around at least a portion of one edge of said cupreous cylinder,mounting said tube and cupreous cylinder in a generally horizontaltelescoped position, rotating said tube and cupreous cylinder at apredetermined speed, positioning an arc overlay welding head adjacentthe top of the subassembly of said tube and cupreous cylinder, saidwelding head being somewhat to one side of a vertical plane through theaxis of said subassembly counter to the direction of rotation of saidsubassembly, feeding a cupreous rod to supply addition metal throughsaid head during said rotation, supplying iiux around said rod and anarc between said rod and said subassembly during said rotation, axiallytraversing said head at a predetermined speed correlated to the speed ofsaid rotation during said rotation of said subassembly and of said rodfeeding to weld said addition metal to lsaid subassembly and saidcupreous cylinder to said tube, and removing substantially all flux fromsaid addition metal following the welding thereof to said subassembly.

l1. ln a method of making a composite cylinder, the steps comprising, incombination, assembling a cylindrical ferrous tube and a cylindricalcupreous sleeve in telescoped relation, the adjoining surfaces of saidtube and sleeve generally defining an interface, rotating said tube andsleeve about a generally horizontal axis, positioning an arc weldinghead near the other side of said sleeve adjacent one edge thereof,moving said head generally parallel to the axis of said sleeve when anarc has been generated between said head and said sleeve and tube,adding copper addition metal by means of an arc to said other side ofsaid sleeve by means of said head during the relative movements of saidhead in respect of said tube and sleeve to overlay said sleeve on saidother side with a spiral band forming an annulus increasing the radialthickness of said sleeve, and generating sufficient heat by means ofsaid arc to bond said tube and sleeve together at said interface withoutmaterial diminution of the radial thickness of said tube.

12. In a method of making a composite brake drum or the like, the stepscomprising in combination, assembling a cylindrical ferrous tube and acylindrical cupreous sleeve in telescoped relation, the adjoiningsurfaces of said tube and sleeve generally dening an interface,fastening said tube and sleeve together rotating said tube and sleeveabout a generally horizontal axis, positioning an arc welding head nearthe other side of said sleeve adjacent one edge thereof, correlativelymoving said head generally parallel to the axis of said sleeve when anarc has been generated between said head and said sleeve and tube,adding copper addition metal by means of an arc to said other side ofsaid sleeve by means of said head during the relative movements of saidhead in respect of said tube Vand sleeve to overlay said sleeve on saidother side with a spiral band forming an annulus increasing the radialthickness of said sleeve, generating sutiicient heat by means of saidarc to bond said tube and sleeve together at said interface withoutmaterial diminution of the radial thickness of said tube, the moltenstate of said metals in said adding and bonding being ambulatoryrelative to said tube, sleeve and annulus while remaining in a stablegenerally horizontal position, and heat treating and finishing saidcylinder in final form.

13. In a method of making a composite cylinder, the steps comprising, incombination, providing a ferrous tube, providing a cupreous sleeve,placing said tube and sleeve in radial juxtaposition, fastening saidsleeve to said tube, preheating said tube, welding cupreous additionmetal to the side of said sleeve away from said tube to bond said tube,sleeve and addition metal into a composite cylinder, cooling saidcomposite cylinder from the tube side thereof during said welding, andhelically moving said tube and sleeve together relative to said additionmetal source during welding.

14. In a method of making a composite brake drum or like cylinder, thesteps comprising, in combination, pro viding a circular steel tube, saidtube having a carbon content not to exceed about 0.25 per centum carbonby weight, providinga circular sleeve of deoxidized copper, assemblingsaid tube and sleeve in telescoped relation with adjoining surfacesthereof close to one another, rotating said tube and sleeve togetherabout a generally horizontal axis, arc overlaying the cylindricalsurface of said sleeve away from said tube with an addition annulus ofdeoxidized copper, generating suliicient heat in said overlaying to weldthe adjoining surfaces of said tube and sleeve together, and controllingconditions of said overlaying and Welding to obtain complete bondingover the entire interface between said tube and sleeve and between saidsleeve and annulus with generally uniform depth of interpenetrationbetween the steel in said tube and the copper adjoining said tube.

l5. In a method of making a composite brake drum or like cylinder, thesteps comprising, in combination, providing a circular steel tube, saidtube having a carbon content not to exceed about 0.25 per centum carbonby weight, providing a circular sleeve of deoxidized copper, assemblingsaid tube and sleeve in telescoped relation with adjoining surfacesthereof close to one another, rotating said tube and sleeve togetherabout a generally horizontal axis, preheatingV said tube at least toabout 350 F., arc overlaying the cylindrical surface of said sleeve awayfrom said tube after said preheating with an addition annulus byhelically applying a deoxidized copper band, generating suflicient heatin said overlaying to weld the adjoining surfaces of said tube andsleeve together, gently cooling said tube during said overlaying, andcontrolling conditions of said overlaying and welding to obtain completebonding over the entire interface between said tube and sleeve andbetween said sleeve and annulus with generally uniform depth ofinterpenetration between the steel in said tube and the copper adjoiningsaid tube.

16. In a method of making a composite cylinder, the steps comprising, incombination, providing a ferrous tube, providing a cupreous sleeve,placing said tube and sleeve in radial juxtaposition, fastening saidsleeve to said tube, preheating said tube, submerged arc overlay weldingcupreous addition metal to the side of said sleeve away from said tubeto bond said tube, sleeve and addition metal into a composite cylinder,cooling said cornposite cylinder from the tube side thereof during saidwelding, helically moving said tube and sleeve together relative to saidaddition metal during such welding, and removing fused flux from saidaddition metal during such relative helical movement.

17. In a method of making a composite cylinder, the steps comprising, incombination, forming a ferrous tube, forming a cupreous sleeve ofcomparable diameter, placing said sleeve and said tube in radialjuxtaposition with one around the other, welding cupreous addition metalaround the side -of said sleeve away from said tube to bond said tube,sleeve and addition metal together, and displacing metal by radialpressure in the copper layer formed by said sleeve and addition metal toform tins therein.

18. In a method of making a composite cylinder, the steps comprising, incombination, forming a ferrous tube, forming a cupreous sleeve -ofcomparable diameter, placing said sleeve and said tube in radialjuxtaposition with one around the other, welding cupreous addition metalaround the side of said sleeve away from said tube to bond said tube,sleeve and addition metal together, slowly cooling them following saidwelding, displacing metal by radial pressure in the copper layer formedby said sleeve and addition metal to form fins therein, and heattreating and sizing said tube and copper layer after said welding.

(References on following page) Refrelnces Citedin 1.114?VA flle ofthispateng UNITED STATES PATENTSk Faries May 28, 1907 Price May 17, 19275 Peron Feb. 15, 1938 Rasmussen Dec. 5, 1939 16 Wallace; .A JuneV 1,1948 Schryber .4 Iuly 11, 1 950 Fergpsson June 17, 1952 FOREIGN PATENTSAustralia Sept. 26, 1940 Great Britain June 11, 1950

